.layer1{width:100%;height:100px;background:tomato;color:black;text-align:center;}
.layer2{width:30%;height:300px;background:salmon;color:saddlebrown;text-align:left;float:left;}
.layer3{width:70%;height:300px;background:red;color:gold;text-align:center;float:left;}
.layer4{width:100%;height:100px;background:yellow;color:green;text-align:center;float:left;}